GMC inline 302 was produced rom 52-60 they are in great demand by nostalga hotrodders and racers. can b made with obscene amounts of horsepower with a great deal of money invested. probally the most legendary is the crossflow WAYNE engineering conversions
i've heard of core engines going for $1000-$1500 the speed parts are just as pricy so expect to spend ALOT per horsepower built
check on
www.inliners.org for info or just google the 302gmc inline 6 theres plenty of info on the web